Teleprinter having a type cylinder which is adjustable by means of a stepping motor

ABSTRACT

A teleprinter for n-step codes having a type cylinder which can be adjusted by a stepping motor by means of rotating the type cylinder in both directions comprises a position comparing device and an n-digit electronic binary counter for counting marks arranged in a row at the circumference of a timing disk carried for rotation with the type cylinder. The position of the timing disk is compared electronically with the received code combination associated with the type to be positioned and the type carrier is operated to the next circumferential position in accordance with the lesser distance of travel in the advance or reset direction of rotation of the type carrier.

United States Patent ['19] Ludwig June 11, 1974 1 1 TELEPRINTER HAVING ATYPE CYLINDER WHICH IS ADJUSTABLE BY MEANS OF A STEPPING MOTOR [75]lnventor: Martin Ludwig, Munich, Germany [73] Assignee: SiemensAktiengesellschaft, Berlin and Munich, Germany [22] Filed: Oct. 31, 1972[2]] App]. No.2 302,569

[30] Foreign Application Priority Data Nov, 4, 1971 Germany 2154899 [52]US. Cl 178/34, 318/685, 197/48 [51] Int. Cl. H041 15/34 [58] Field ofSearch 178/34, 35, 38; 197/48, 197/6.6; 318/467, 685

[56] References Cited UNlTED STATES PATENTS 2,989,680 6/1961 Weiser eta1 318/467 1/1968 Tutert et a1 178/34 INPUT REGISTER COMPARING DEVICE[37 TEST BINARY TYPE COUNTER CYLINDER TINING DISK CONTROL CIRCUIT (F 1G.41

Takenaka 178/34 Markkanen et a1 318/685 Primary ExaminerWilliam C.Cooper Assistant ExaminerGerald Brigance Attorney, Agent, or Firm-Hill,Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT Ateleprinter for n-step codes having a type cylinder which can beadjusted by a stepping motor by means of rotating the type cylinder inboth directions comprises a position comparing device and an n-digitelectronic binary counter for counting marks arranged in a row at thecircumference of a timing disk carried for rotation with the typecylinder. The position of the timing disk is compared electronicallywith the received code combination associated with the type to bepositioned and the type carrier is operated to the next circumferentialposition in accordance with the lesser distance of travel in the advanceor reset direction of rotation of the type carrier.

2 Claims, 4 Drawing Figures PATENTEDJUH H 1914 3.816356 SHEET 1 DE 2Fig.2 TIMING I F i 9] DISK T8 2 INPUT REGISTER COMPARING FLIP FLOP iDEVICE TIMING TEST BINARY T COUNTER CYLINDER B ZUUkHz I TRANSDUCERTIMING DISK (FIG.3)

TIMING PULSE INPUT SST H I CONTROL cmcun VO/R (FICA) PATENTEBJUM 1 IBMSHEET 2 [IF 2 ST Sc hT Vo/R FLIP FLOPS P ABLE 0P (.ESGSI M0 FL SSTTELEPRINTER HAVING A TYPE CYLINDER WHICH IS ADJUSTABLE BY MEANS OF ASTEPPING MOTOR BACKGROUND OF THE INVENTION 1. Field of the InventionThis invention relates to a teleprinter, and more particularly to ateleprinter having a n-stepping code comprising a type cylinder whichcan be adjusted by a stepping motor by means of rotating the typecylinder in both directions and comprising a code-comparing devicehaving marks upon a disk or roller which can be scanned and which arerotated along with the type carrier.

2. Description of the Prior Art The prior art recognizes the applicationof an n-digit electronic binary counter with a teleprinter having aconstantly rotating type number, which electronic binary counter can becontrolled by way of stepping marks arranged in a row at thecircumference of a timing disk and means for scanning the comparingmarks whereby the position of the type cylinder is electronicallycompared with respective code combinations associated with the typecylinder which is to be adjusted.

SUMMARY OF THE INVENTION The primary object of the present invention isto providea teleprinter of the type mentioned above comprising acomparing system having a binary counter, as described above, and asimple system by which it can easily be decided whether the nextprinting location can be reached on the shortest path of travel by meansof advancing or resetting the type carrier.

The foregoing object is realized, according to this invention, in such away that a test binary counter with a much higher timing frequency, forexample, with a 200 kHz timing frequency, which can be permutated in theadvance direction, is provided for simulating the demanded adjustment ofthe binary counter. A timing counter which can be controlled by way ofthe test binary counter is controlled when half of the number ofprintingpositions or less along the circumference are counted before theend position is reached to effect an adjustment of the stepping motor inthe advance direction and if half of the number of printing positions ormore is exceeded, will effect an adjustment of the stepping motor in thereverse direction.

According to a further development of the invention, a solution whichcan be realized simply and inexpensively, for example, in accordancewith the prior art MOS technique, is provided in that a flip-flop stageis connected to the timing counter which, after a teleprinter symbol hasbeen stored, is effective in the sense of influencing a control circuitwhich reacts according to logical switching states in one or the othersense and influences the. stepping motor,f1rst of all, in. the advancedirection. The timing counter influences a control circuit, possiblywhile reaching a position corresponding to half the passed-throughprinting positions, in such a way that the stimulation is completed andthus the reset of the stepping motor is caused while the advance controlof the stepping motor becomes effective when lower timing numbers aredetected before reaching the next printing position.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantagesof the invention, its organization, construction and operation will bebest understood from the following detailed description of an embodimentthereof taken on conjunction with the accompanying drawings, on which:

FIG. 1 is a schematic logic diagram of the system according to theinvention;

FIG. 2 is a plan view of the timing disk TS employed in FIG. 1;

FIG. 3 is a more detailed logic diagram of a control circuit employed inFIG. 1; and

FIG. 4 is a schematic logic diagram of a circuit for controlling thestepping motor.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, fivesteps of a teleprinter symbol are received in a register ER in ateleprinter in accordance with a five code and 100 Baud printing speed.The register ER comprises an electronic series/- parallel converter. Thetype carrier of the printing system is embodied as a type cylinder T'lwhich is adjustable in either direction by means of a stepping motor SM.A timing Disk TS, which is illustrated in a plan view in FIG. 2, isattached upon a shaft 2 which defines the axis of rotation of the typecylinder TT. The timing Disk TS comprises marks 1 at a predeterminedradial distance from the shaft 2, which marks are scanned by atransducerW. A mark 3 is carried on the disk T8 at a different radiusand appears only once per revolution and serves for producing asynchronizing pulse which is not essential for the invention and istherefore not further treated herein.

The contents of a five-digit binary counter BZ which is provided in thecircuit respectively correspond to the binary numbers by which the codecombination can be expressed which is associated with the instantaneousposition of the type cylinder TT. The construction of the binary countermay, for example, correspond to that disclosed in the German LettersPat. No. 1,055,047. A comparing device V compares the symbols stored inthe input register ER (with the bits in parallel form) with the contentsof the binary counter 82, on the one hand, and on the other handcompares with the contents of a test binary counter PZ. Both countersare switched further over one digit in the five-digit dual system whenan individual timing pulse arises.

More specifically, the development when the counters are switched is asfollows. When the contents applied to the comparing device V from theinput register ER and from the test binary counter PZ coincide, acharacter printing process is effected directly by way of an output A.In the case of non-coincidence, the adjusting movement is stimulated inthe test binary counter PZ before the adjusting movement of the typecarrier TT at a 200 kHz frequency as follows. Since a maximum of 16steps are required for adjusting in an advance or reset motion in theexample as selected, microseconds are required. This time is negligiblecompared with the mechanical adjustment time (65 miliseconds with Bd).

After a symbol has been stored in the input register ER, a signal isproduced and further processed in a control circuit ST, as illustratedin FIG. 3. A bistable flipflop circuit SpI is connected into thiscontrol circuit ST and is therefore activated by way of a monostableflipflop circuit MK, or an OR gate G6 and the AND gates G2, so that theinformation stored in the binary counter BZ reflecting the position ofthe type carrier TI" is transferred by the test binary counter PZ.Simultaneously, a timing counter TZ and a flip-flop stage K are reset.The position of the flip-flop stage K obtained in this manner containsthe direction that the stepping motor SM must be driven in a directionherein called the advance direction for a control circuit SST for thestepping motor SM. After the contents of the binary counter 82 has beentransferred over into the test counter PZ, the monostable flip-flopcircuit MK will flip back and activate a 200 Khz timing pulse generatorfor the test binary counter TZ, by way of a gate G1,

after which the test binary counter P2 is switched further in accordancewith this timing frequency. The comparing device V thereby compares theinformation stored in the input register ER with that of the furtherswitched test binary counter PZ. The timing counter T2 is switchedfurther in accordance with the same timing frequency. If the comparingdevice V detects coincidence with the contents of the input register ERand the test binary counter PZ, then the simulated adjustment is endedin the test binary counter PZ and the adjustment of the type carrier TTis initiated by the stepping motor SM by way of the bistable flip-flopstages Spl and Sp2. If the timing counter PZ has not reached thecounting value 16 in the meantime, the flip-flop stage K which isconnected to the timing counter TZ is reset. As was mentioned before,this means that the stepping motor SM is driven in an advance direction.If the timing counter has reached the position 16 again before thecomparing device V finds coincidence between the contents of the inputregister ER and the contents of the test binary counter PZ, then a pulsewill be emitted from the timing counter TZ which, and in the same manneras the comparing device V in the other case, will initiate the adjustingprocess of the type carrier TT by means of the stepping motor SM by wayof the bistable flip-flop stages Spl and Sp2. However, the circuit STwill simultaneously place the flip-flop K in a position which announcesa reset motion of the stepping motor SM to the control circuit SST forthe stepping motor SM. Timing pulses ZT are generated due to therotation of the timing disk TS pass the transducer W as the type carrierTT is adjusted and reach the binary counter BZ whereby the latter isselectively switched further forward or backwardthe flip-flop stage Keither activates the AND gate G3 or the AND gate G4-due to the symbolpulses ZT by way of one of the gates G3 or G4, respectively.Simultaneously, the contents of the binary counter BZ are furtherprocessed and applied to the test binary counter PZ by way of the gatesG2, and the test binary counter PZ makes this information available forthe comparing device V.

During the simulated adjustment of the test binary counter PZ by the 200kHz timing pulses, a gate G7 is blocked so that the comparing device Vcannot further process any information to the type printing device byway of the output A if the contents of the input register ER and thecontents of the test binary counter PZ coincide. Only after theadjusting process of the type carrier TT by way of the stepping motor SMhas been completed will this printing order be further processed.

Referring to FIG. 4 there is illustrated a stepping motor and thecontrol circuit SST required for controlling the stepping motor. Thestepping motor SM in the selected example has three poles, i.e., itcomprises three excitation windings. Corresponding to these threeexcitation windings, a three-stage shift register R2 is provided in thecontrol circuit. Depending on the position of the shift register, one ofthe excitation windings 'of the stepping motor SM will be excited by wayof a corresponding amplifier circuit VS. The stepping frequency issupplied to the shift register by a timing generator SchT (notillustrated in detail) by way of an AND gate G5 when the correspondinginformation concerning the adjusting movement is provided by way of thebistable flip-flop stage ST. The direction of the pulse supply for theshift register RZ is predetermined, depending on the position of theflip-flop stage K by way of the gates G8 and G9.

Although I have described my invention by reference to a specificillustrated embodiment thereof, many changes and modifications of theinvention may become apparent to those skilled in the art withoutdeparting from the spirit and scope of the invention. 1 therefore intendto include within the patent warranted hereon all such changes andmodifications as may reasonably and properly be included within thescope of my contribution to the art.

I claim:

1. A teleprinter for n-step codes comprising: a rotatable type cylinder,a stepping motor connected to said type cylinder for rotating said typecylinder in both directions, a position comparing device comprising atiming disk mutually rotatable with said type cylinder and carryingthereon a plurality of marks, means for reading said marks as said typecylinder is rotated, an n-digit electronic binary counter connected tosaid reading means for storing the position of said type cylinder, meansfor receiving an n-digit code corresponding to a symbol to be typed,means for comparing the contents of said receiving means and thecontents of said n-digit electronic binary counter and producing aprinting pulse in response to coincidence, and means for controlling therotation of the type carrier over the shortest path for the nextcircumferential position thereof including a test binary counterinterposed between said n-digit electronic binary counter and saidcomparing means, means for advancing said test binary counter tosimulate advancement of said n-digit electronic binary counter toproduce a simulated demanded adjustment of said biary counter for thenext circumferential position of said type cylinder, a timing countercontrolled by said test binary counter for controlling the operation ofsaid stepping motor in the advance direction if half the number ofprinting positions or less along the circumference of said type cylinderare counted before the end position is reached and in the oppositedirection if half the number of printing positions is exceeded.

2. A teleprinter according to claim 1 comprising a flip-flop stage and acontrol circuit, said flip-flop stage connected to said timing counterand responsive to receipt of a symbol to be typed to cause said controlcircuit to effect operation of said stepping motor in the advancedirection, said timing counter connected to said control circuit andoperable to cause said control circuit to effect operation of saidstepping motor in the opposite direction when a position is reachedcorresponding to half the printing positions.

1. A teleprinter for n-step codes comprising: a rotatable type cylinder,a stepping motor connected to said type cylinder for rotating said typecylinder in both directions, a position comparing device comprising atiming disk mutually rotatable with said type cylinder and carryingthereon a plurality of marks, means for reading said marks as said typecylinder is rotated, an n-digit electronic binary counter connected tosaid reading means for storing the position of said type cylinder, meansfor receiving an n-digit code corresponding to a symbol to be typed,means for comparing the contents of said receiving means and thecontents of said n-digit electronic binary counter and producing aprinting pulse in response to coincidence, and means for controlling therotation of the type carrier over the shortest path for the nextcircumferential position thereof including a test binary counterinterposed between said n-digit electronic binary counter and saidcomparing means, means for advancing said test binary counter tosimulate advancement of said n-digit electronic binary counter toproduce a simulated demanded adjustment of said biary counter for thenext circumferential position of said type cylinder, a timing countercontrolled by said test binary counter for controlling the operation ofsaid stepping motor in the advance direction if half the number ofprinting positions or less along the circumference of said type cylinderare counted before the end position is reached and in the oppositedirection if half the number of printing positions is exceeded.
 2. Ateleprinter according to claim 1 comprising a flip-flop stage and acontrol circuit, said flip-flop stage connected to said timing counterand responsive to receipt of a symbol to be typed to cause said controlcircuit to effect operation of said stepping motor in the advancedirection, said timing counter connected to said control circuit andoperable to cause said control circuit to effect operation of saidstepping motor in the opposite direction when a position is reachedcorresponding to half the printing positions.